dohabandit's profile

Tutor

 • 

13 Messages

Monday, October 11th, 2021 7:39 PM

U-Verse DVR (Cisco ISB7500) ethernet port only connects at 10Base-T? (10Megabits/sec)

I had my home upgraded to AT&T fiber. Now my DVR is crap, lots of video corruption problems (looks like DCT blocks).

I was using the DVR before with the 2Wire gateway and a COAX home run between DVR and gateway using MOCA/HPNA.

The DVR is now no longer connected to COAX and is using ethernet, however the ethernet port will only link at 10M. If I try to link it at 100, or gig speed, the interface won't come up. (I am connecting to a managed Cisco 3750X switch, and I am a network engineer).

I have tried forced speed/duplex, but it only connects at 10M, is the interface on that DVR designed to link at 100/1000base-t speeds?

It seems that the bandwidth reduction is causing problems when my family has a show recording and also trying to play from the DVR using a STB in another room (also directly wired via ethernet).

I have no errors, discards, or other interface statistics that would indicate a network problem.

ACE - Professor

 • 

8.1K Messages

3 years ago

What model gateway are you using?

It smells like you may need a new gateway. When I upgraded to fiber, I didn't see anything wrong with my TV. But...if you're using an older gateway, it's possible you're not getting 100Mbps or faster speeds.

I'd call 800-288-2020 and ask for tech support.

ACE - Professor

 • 

1.5K Messages

3 years ago

@dohabandit 

Tagging @JefferMC    

The problem is almost certainly caused by the switch.  Are you able to configure it to enable IGMP support?   U-verse TV traffic requires multicast to work.  

ACE - Expert

 • 

36.8K Messages

3 years ago

It sounds like your switch is having issues negotiating link rates with the AT&T Gear.  Most, if not all, AT&T DVRs and TV Receivers are 10/100 and will not work at Gigabit speeds, so if you're trying to force a speed, make sure it's 100 Mbps, not 1000 Mbps.

A second possible option is back pressure from a Wireless Router.  The 3750-X has multicast routing/IGMPv3 support, so you might consider configuring that for the AT&T TV gear.  The 3750-X also supports VLAN, so it might be easier to create a VLAN with a second port from the Gateway and all the AT&T IPTV gear, just to isolate it on its own network.

More than 2 HD channel will saturate a 10 Mbps link, so the DVR has to have more than 10 Mbps.  Your other IPTV devices might survive it.

ACE - Professor

 • 

8.1K Messages

3 years ago

Can someone explain to me why a TV receiver would need a certain speed? I noticed no picture quality increase when I switched from coax to ethernet. I noticed no PQ increase when I switched from "regular" internet to fiber.

The only time I noticed a PQ increase was over 10 years ago when AT&T did something on their end. (I think.)

Since U-Verse streams use about 8Mb per stream, shouldn't anything above about 24Mbps be good enough? I suppose if someone had 24 or slower and wanted to use the internet, they could probably see a decrease in PQ. (Which could also explain my second paragraph, but I always thought TV and internet was a different bunch of signals.)

ACE - Expert

 • 

36.8K Messages

3 years ago

U-verse needs about 2 Mbps for SD, 6 Mbps for HD.  The DVR needs to be able to handle multiple streams in and out, so it will often need more than 10 Mbps.  AT&T's U-verse IPTV signal does not quietly scale down or up as does Netflix and other streaming providers.  You need what you need.  Faster will not make the picture any better, slower will not make it more grainy (it will just pause/skip/pixelate, etc. from lost data).

There is also a brief period when you first change channels where all receivers will need twice the stream width (one unicast stream which lasts up to about 10 seconds after the channel change, and the multicast stream which will start after a few seconds and will continue until you change channels again or turn the box off). The unicast is abandoned as soon as the multicast picks up, so it is a very brief period.

So, if you're watching HD, 10 Mbps is not enough, you must have at least 12 for all receivers, and DVRs may need much more.  So, I'd recommend at least 100 Mbps Ethernet.  1000 Mbps is fine, but is not necessary.   (I don't recommend the use of 10/100 Mbps switches because they may not actually forward traffic fast enough).  The protocol being used over Coax provides up to about 110 Mbps, IIRC.

ACE - Professor

 • 

8.1K Messages

3 years ago

Sooo... I believe U-Verse allows for eight different TVs. If all were watching live TV at the same time, 8*6 is 48. If all were changing channels at the same time, 48*2 is 96.

If other stuff is "always online" such as doorbells or whatnot, that's going to be more bandwidth right there.

I guess I don't really think about that side much, since I've had enough bandwidth for quite some time, especially since I have just one wireless receiver and I only use it a few hours a week.

But I can see why the newer DVR (six streams) requires Internet 1000. Under a particular circumstance or two, Internet 100 wouldn't be enough.

(edited)

ACE - Expert

 • 

36.8K Messages

3 years ago

I think the 6 streams was more of a perk to get people to upgrade.  4 streams was built around the 32 Mbps profile, so a 50 Mbps profile could have handled 6 fine. 

U-verse TV does allow for 8 TVs, but not all of which could be pulling unique live streams; some of it would have had to be shared multicast and some coming from the DVR.

Video doorbells can send a bit of data upstream when active, but that's in a different direction; most wired communication is duplexed, so you can send and receive at the same time.

ACE - Professor

 • 

8.1K Messages

3 years ago

Truth about the eight TVs.

Receivers 1-4 could be different live TV.

Receivers 5-7 would have to be recorded TV.

The DVR watching recorded TV would be 8.

Since one stream on two different TVs only counts as one stream, I suppose it could be possible to have more than 8 TVs.

But as we get more and more into the "Internet of Things" and heavy downloading, there will soon be a time when 100Mbps internet is looked at like 6mbps is. (And I remember when 12Mbps was fast.)

ACE - Expert

 • 

36.8K Messages

3 years ago

I remember when 0.056 Mbps down / 0.033 Mbps up was as good as most people got for residential Internet connections.  I remember when a T1 connection (1.544 Mbps) was the standard for a business Internet connection.

Of course I remember when most computers weren't connected to any network at all.

ACE - Professor

 • 

1.5K Messages

3 years ago

Wow has this thread gotten sidetracked. 😜

I wanna hear back from our networking expert OP on how things are going!

ACE - Professor

 • 

8.1K Messages

3 years ago

A bunch of high schools in the area (including mine) supposedly shared a single T1 line. I have no idea how that was possible, but whatever.

It was quite slow during the week, but I heard it flew on weekends.

Tutor

 • 

13 Messages

3 years ago

Yeah, it's not linking using anything other than 10base-T. If I use auto-neg, it negotiates 10base, if I force speed & duplex, it won't link at all with speed 100 / duplex full. I am old school network engineer and have also worked in the CATV industry (building IPTV headends believe it or not), so I already have the IPTV stuff in it's own vlan and have sorted out the multicast. I don't need any sort of PIM-SM or other features in my smallish home network.

I just couldn't find ANYWHERE online the technical specs for the Cisco STB. Was wondering if it was gigabit capable, or was locked to 10M. As others have indicated, 10M would often not be enough depending on how much and what quality of content was streaming which is what I am running into. My port statistics show a very clean interface though. No errors, discards, etc. Just not enough bandwidth...

I have tried switching out cables, switching out ports on switch, linking to even entirely different switches all with known-good/tested ports. Put a switch 3' away, same issue. I think all that is left is there is a transceiver problem in the Cisco STB / DVR which really (Edited per community guidelines). Will have to tell my wife to hurry up and watch all her saved shows because a replacement part will likely loose all her DVR'd content. Have heard people talking about swapping the drives around, but not sure that is an option or just a rumor.

(edited)

ACE - Expert

 • 

36.8K Messages

3 years ago

There have been negotiation issues with various and sundry pieces of the U-verse platform, but mainly it's been with the Gateways.  (WD NAS boxes are the biggest offender here).

One thing that might work would be the same hack we recommended to get around that issue: get a $15 five-port switch and connect your DVR to your Enterprise Switch through that.  Ugly: Yes.  Shouldn't be necessary: right.  Might be a workaround: worth trying.

I have a Dell-branded Enterprise Ethernet switch in my home network that won't play well with a  Silicon Dust tuner.  So, yeah, it's connected through a 5 port Netgear.   The IPTV gear doesn't have any issues negotiating the 100 baseTX connection with the Dell switch; it just gives me an orange light instead of the usual green.  Because I'm using a single Ethernet run to my living room, I have a smaller Enterprise Ethernet switch there and am running a small tagged VLAN between them.  The receiver connected to the remote switch negotiates fine, too.

(edited)

ACE - Professor

 • 

1.5K Messages

3 years ago

@dohabandit

Correct, U-verse hardware is not gigabit capable.  
Also, I wouldn’t bother asking for a replacement DVR.  The result will be the same.  


@JefferMC 

I also use a cheap 5 port Ethernet switch in the attic to connect my DVR to the gateway.  

(edited)

Tutor

 • 

13 Messages

3 years ago

Manufacturer NOKIA
Model Number BGW320-505

I have a brand new GPON gateway. My network is smoking fast, and its probably more complex than most homes. I run a Cisco aironet mesh with a vWLC. That runs multiple SSIDs and drop those into different vlans. My guest and IPTV vlan are on the outside of everything and are layer-2 all the way to the GPON gateway. 

Replacing the gateway or some of the other suggestions wouldn't change the fact that the DVR is connecting at 10base-T which is the real problem here. This DVR is long in the tooth and was only connected via MOCA/HPNA to the old gateway before I got the GPON upgrade. I suspect it has damage to the transceiver of some sort. That HPNA stuff is really interesting to see on a spectrum analyzer btw, looks like a broad spectrum signal with a lot of narrow peaks, like the fingers on a comb. Wreaks havoc if you connect that stuff back into the return path of a CATV system.


NEED HELP?